Users' experience of media content such as films, music and lectures, has been enhanced through advances in audio technology. Technological advances have improved audio transmission quality and provided tools to the user that enhance the user's experience.
One of the key technological enhancements in audio transmission is ‘streaming’. Streaming can be defined as a technique for transferal of data while continually processing the data. For example, a computer can take advantage of streaming technology to render audio during a download. Streaming is thus useful for users who wish to listen to extensive sections of audio without having to wait for transfer of the entire data. Rather than downloading the file in its entirety before playing, users can start listening to the audio before the transmission is completed
When streaming audio over a network, traffic problems are often encountered and the delivery of a steady stream of packets to the client is not always possible. During these periods of congestion, the user may experience disruption in service. For example, should network congestion occurs when using a REAL AUDIO® player, the player will cease rendering audio and display the words ‘buffering’ accompanied by flashing red and green lights (see www.real.com). This buffering occurs when the rate at which packets arrive from the server to the client is slower than the rate from client to user. To limit the occurrence of interruption, streaming clients employ a buffer, typically embodied in a segment of memory, of most recently received audio packets.
Typically the network may slow down or speed up for periods of time, corresponding to low or high bandwidth availability. During times of high bandwidth, the buffer is filled; when transmission degrades, packets drawn from the buffer ensure a smooth rendering from the client to the user. The buffer operates in a First In First Out (FIFO) manner, whereby only the most recent bytes are stored. This is accomplished by constantly playing from the buffer while simultaneously inserting new bytes.
As the frequency of network problems increase, the contents of the buffer gradually decrease. When the buffer has been depleted, playing may cease.
Existing technology for navigation within audio samples provides users with basic navigational functions such as ‘fast forward’, ‘rewind’ and ‘pause’. In addition to these basic functions, current technologies are capable of more advanced functions such as ‘time compression’, which enables the speeding up or slowing down of audio content without changing the pitch or audio quality. For instance, Creative Technology Ltd's EAX Technology® offers advanced audio functionality and performance for digital audio. EAX Technology® includes time-scaling adjustments in order to change the speed of the audio to suit the user's individual preferences.
In addition to time-scaling, InterVideo, Inc has produced a DVD player that possesses a “time stretching” feature. “Time stretching” allows a user to play a three hour DVD film in two hours, by adjusting the playback speed from half-speed to double-speed while still maintaining the original audio quality of the film.
Another advanced audio product is embodied in a DIR911 audio processor of Eventide Inc., which features an Intelli-Clear® speed control. The Eventide audio processor DIR911 provides the option to rewind or fast-forward an answer phone message in small segments of 1.25 seconds at a time.
“SpeechSkimmer” is a user interface for skimming speech recordings developed by the Speech Research Group at the MIT Media Laboratory. “SpeechSkimmer” enables a user to hear recorded sounds quickly at several levels of detail by using simple speech processing techniques. “A continuum of time compression and skimming techniques have been designed, allowing a user to efficiently skim a speech recording to find portions of interest, then listen to it time-compressed to allow quick browsing of the recorded information, and then slowing down further to listen to detailed information.” (Barry Arons ‘SpeechSkimmer: Interactively Skimming Recorded Speech. Proceedings of UIST 1993: ACM Symposium on User Interface Software and Technology. ACM Press. Nov. 3-5, 1993. Atlanta.)